Brachytherapy (radioactive seed implantation) is an option for curative treatment chosen by up to 35,000 of the 233,000 men who develop prostate cancer in the United States each year. Brachytherapy can produce excellent treatment outcomes, but those outcomes vary depending on the quality of the treatment delivered, which in turn depends on the positioning of the seeds. C4 Imaging has successfully demonstrated and received FDA 510(k) clearance for an MRI Marker based approach to radioactive seed localization. It addresses the need to improve treatment assessment (dosimetry) for men who undergo prostate brachytherapy through better anatomical delineation. An enhanced MRI/CT Marker will allow clinicians to incorporate both MRI's optimal anatomical imaging and CT's device identification to further improve treatment planning and assessment. The overall goal of this proposal is to develop and implement an enhanced multi-modality MRI/CT marker by modifying the previous FDA approved C4 MRI Marker. Improvements in device fabrication could be achieved if the current liquid fill of each MRI Marker were replaced by porous ceramic insert containing the positive-signal MRI C4 solution. Prototyping has identified that a highly porous ceramic zirconium core could address this and would add CT clinical imaging capabilities to the device. The MRI/CT Markers will undergo ISO 10993 biocompatibility testing before being validated in post-production, phantom-based MR and CT functional assessment of production intent finished devices. Fully validated devices will then be prepared for clinical use through a full assembly cycle that includes gamma and ethylene oxide sterilization and assessed for radioactive seed localization in a canine tumor model. The data generated will be used to support FDA 510(k) approval. C4 Imaging has demonstrated success in this area of research and is qualified to perform the work outlined in this proposal. The team is active in developing MRI technology based on a positive-signal MRI solution; have experience in medical device development and fabrication; and have expertise in the clinical use and marketing of medical devices used in prostate cancer.